Sealed crown for watch casing

ABSTRACT

The sealing device for a control member ( 17 ) is provided with a shaft ( 16 ) passing through a sealed casing and comprising a tube ( 1 ) driven into a bore ( 3 ) of the casing ( 4 ). A shaft ( 16 ) of the control member ( 17 ) is engaged in the tube ( 1 ) and at least one joint ( 18, 19 ) ensures normal sealing between this tube and this shaft. It comprises a compression key ( 6 ) screwed on the tube ( 1 ) comprising an upper portion ( 8 ) overlying the tube ( 1 ) and surrounding the shaft ( 16 ) of the control member ( 17 ). A compression joint ( 15 ) is disposed in the space comprised between the upper portion ( 8 ) of the compression key, the tube ( 1 ) and the shaft ( 16 ).

[0001] The present invention has for its object a sealing device for a control member passing through the wall of a watch casing such as a setting crown or a pushbutton for example.

[0002] The object of the present invention is to provide a sealed device for a control member passing through the wall of a watch casing, which permits ensuring normal sealing, for example resistant to 10 Atmospheres, during use of the control member and increased sealing when the control member is not used, for example resistant to 100 Atmospheres.

[0003] Another object of the present invention is to avoid, during passage from normal sealing to increased sealing, any angular and/or axial movement of the control member to avoid any interaction with the control mechanism.

[0004] Still another object of the invention is the provision of such a sealing device which will be simple to produce and to mount and which can be easily dismounted by post-sale service, for example to change the seals.

[0005] The present invention has for its object a sealing device for a control member passing through a watch casing, which overcomes the drawbacks of the existing devices and permits achieving the objects set forth above, this sealing device being distinguished by the characteristics set forth in claim 1.

[0006] The accompanying drawings show schematically and by way of example three embodiments and two modifications of the sealing device according to the invention.

[0007]FIG. 1 is a cross-sectional view of the sealing device in the increased sealing position.

[0008]FIG. 2 is a cross-sectional view of the sealing device in the normal sealing position, for actuating the control member.

[0009]FIG. 3 is a bottom view of the compression key.

[0010]FIG. 4 is a side view of the compression key.

[0011]FIGS. 5 and 6 are cross-sectional views on the line A-A of FIG. 4 in the open position, respectively the closed position of the compression key.

[0012]FIG. 7 shows in cross-section a second embodiment of the sealing device.

[0013]FIG. 8 shows in cross-section a third embodiment of the sealing device.

[0014]FIGS. 9 and 10 show in cross-section modifications in the shape of the embodiment shown in FIG. 8.

[0015] The present sealing device for a control member passing through a casing, in particular a watch casing, is applicable also to pushbuttons which more particularly have a setting shaft or crown. This device permits considerably increasing the sealing of the control member. With the help of this device, normal sealing of about 10 Atmospheres which is present during manipulations of the control member can be increased to a value of the order of 100 Atmospheres by a simple manipulation of a compression key, which manipulation also immobilizes the control member in its inactive position.

[0016] Moreover, as will be seen later, this sealing device is easy to produce and to mount on a sealed casing because it comprises only few pieces that are easy to machine. Moreover, the after sale service is simplified because dismounting the device, particularly to change the seals, can take place easily without returning to the factory by a watchmaker present at the point of sale.

[0017] The sealing device according to the present invention is shown in the accompanying drawings in relation to the sealing of a setting crown and comprises a tube 1 comprising an internal cylindrical portion and an external cylindrical portion of larger diameter provided with a screw thread 2. In its lower portion, this tube 1 comprises a cylindrical bore whilst in its upper portion the tube 1 has a central conical opening flaring toward the outer end of the tube 1.

[0018] In the service position, the internal cylindrical end of smaller diameter is forcibly driven into a bore 3 passing through the sealed casing 4. Below the screw threads 2 of the tube 1 there is an annular throat in which is disposed an O-ring joint 5 coacting with this tube 1, with the external surface of the casing 4 and, as will be seen later, with the compression key 6.

[0019] The compression key 6 of the first embodiment shown in FIGS. 1 to 6 comprises a body provided with an internal screw thread corresponding to the screw thread 2 of the tube and screwed on the latter. This body is provided with a sleeve 7 whose internal surface coacts with the joint 5 and with an upper portion 8 having the shape of a crown whose lower surface has a conical portion. The body of this compression key 6 moreover comprises two external wings 9 permitting its manipulation by the user.

[0020] Thus, when the tube 1 is driven into the bore 3 of the casing 4 and the compression key 6 is screwed onto this tube, the joint 5 ensures sealing between the compression key 6 and the tube 1 and protects the screw threading 2. Moreover, this joint 5 ensures a certain friction between the tube 1 and the compression key such that the latter will not move untimely, but only under the effect of a couple which the user can impose on it.

[0021] As seen in FIGS. 3, 5 and 6, the sleeve 7 of the compression key 6 is milled about 180° of its periphery so as to create two abutments 10, 11 adapted to coact with the head of a screw 12 screwed into the watch casing and thus limiting the rotation of the compression key to about 180°. The periphery of the compression key 6 comprises a recess 13 permitting access to the screw head 12 to emplace it or remove it for dismounting the sealing device and replacing the seals.

[0022] Screw 12 constitutes a stop coacting with the abutments 10, 11 of the compression key to limit the rotation of the latter between an open position and a closed position.

[0023] The sealing device moreover comprises a split ring, preferably of Delrin or of steel, of conical shape, disposed in the narrow portion of the internal cone of the tube 1. On this ring 14 is disposed an O-ring joint 15 whose upper portion bears below the upper portion 8 of the compression key.

[0024] In the open position, unscrewed, of the compression key 6, this joint 15 is only partially compressed (FIG. 2) whilst in the closed position, screwed in, of the compression key, this joint 15 is totally compressed (FIG. 1) between the upper portion 8 of the compression key, the tube 1, the ring 14 and the shaft 16 of the crown 17.

[0025] The setting crown 17 comprises a shaft 16 passing through the upper portion 8 of the compression key 6, the ring 14 and the cylindrical portion of the tube 1. The end of the shaft 16 of the crown 17 is provided with two O-ring joints 18, 19 disposed in a circular throat provided in the external cylindrical wall of the shaft 16. These joints 18, 19 ensure normal sealing of the order of 10 Atmospheres, between the tube 1 and the shaft 16 when the compression key is open. In this position, the user can actuate the setting shaft 16 axially and in rotation.

[0026] When the compression key is screwed in or closed, the joint 15 is totally compressed and forces the splint ring to the bottom of the cone of the tube 1 and against the setting shaft 16. In this position, the sealing is very substantially increased and reaches a value of 100 Atmospheres and the shaft 14 is blocked.

[0027] The shaft 16 of the setting crown comprises, in the usual way, an axial screw thread in its internal end permitting coupling to the setting shaft properly so called of the mechanism.

[0028] Thanks to this sealing mechanism, there is achieved a high sealing, 100 Atmospheres, in the closed position of the compression key and the setting shaft is blocked. The watch can be worn in this position and it is only during setting of the time of the movement that the user frees the compression key to permit this function. In this open position, the sealing is nevertheless guaranteed at a normal value of the order of 10 Atmospheres.

[0029] A supplemental advantage of the sealing device resides in the fact that during passage from the open position to the closed position of the compression key and vice versa, the shaft 16 of the crown 17 undergoes no axial displacement which could damage the mechanism.

[0030] Moreover, if the screw pitch used to screw the compression key onto the tube comprises a left hand thread, the gripping of this compression key, even if the user simultaneously turns the crown 17, as he might accidentally do, the mechanism cannot be damaged. Thus, the rotation for gripping of the compression key takes place in the reverse direction of the rotation of the crown 17 for setting the watch. There is thus never a risk of over-tensioning of the mainspring.

[0031] In the second embodiment of the sealing device shown in FIG. 7, the compression key 6 has no wing 9 but rather a manipulating member is constituted by a notched crown. In this embodiment, the tube 1 comprising the screw thread 2 comprises a central cylindrical passage over all its length and the joint 15 is disposed between the end external surface of the tube 1, the upper portion 8 of the compression key 6 and the shaft 16 of the crown 17. In this embodiment, the compression joint 15 is mounted without the split ring 17.

[0032] In the third embodiment, shown in FIG. 8, the manipulating member of the compression key 6 is formed by a milled or striated cone and the crown 17 is mounted on the shaft 16 so as to be able to slide axially against the action of a spring 20 by means of a ring 21 driven into the crown 17 serving as an axial abutment. The skirt of the crown 17 comprises an internal cone corresponding to the external cone of the compression key. Thus, when the user pushes on the crown 17 against the action of the spring 20, he can drive in rotation the compression key 6 with the help of the crown 17 by coupling of the two cones.

[0033] In the modifications illustrated in FIGS. 9 and 10, the drive of the compression key 6 by the crown 17 takes place by the wings or by six flats that couple when the crown 17 is pushed against the action of the spring 20.

[0034] In these three last embodiments (FIGS. 8-10) the crown 17 is axially movable against the action of a spring 20 relative to the shaft 16 and this axial movement engages and disengages a drive coupling between the crown 17 or the ring 21 which is secured to it, and the compression key 6. The user can thus screw or unscrew the compression key by pushing on the crown 17 and driving the latter in one direction or the other. This coupling can be effected by the wings 22 and corresponding recesses 23 (FIG. 9) or by six female flats 24 and six male flats 25 (FIG. 10). 

1. Sealing device for a control member (17) provided with a shaft (16) passing through a sealed casing comprising a tube (1) driven into a bore (3) of the casing (4); a shaft (16) of the control member (17) engaged in the tube (1) and at least one joint (18, 19) ensuring normal sealing between this tube and this shaft, characterized by the fact that it comprises a compression key (6) screwed onto the tube (1) comprising an upper portion (8) overlying the tube (1) and surrounding the shaft (16) of the control member (17) and by the fact that a compression joint (15) is disposed in the space comprised between the upper portion (8) of the compression key, the tube (1) and the shaft (16).
 2. Device according to claim 1, characterized by the fact that it comprises means limiting the angle of rotation of the compression key to a value less than 360°.
 3. Device according to claim 1 or claim 2, characterized by the fact that the compression key comprises means for driving it in rotation.
 4. Device according to one of claims 2 or 3, characterized by the fact that the means limiting the angle or rotation of the compression key comprise a stop (12) fixed in the casing (4) and a milling provided in the compression key defining two abutments (10, 11).
 5. Device according to claim 4, characterized by the fact that the stop is constituted by a screw (12) and that the periphery of the compression key comprises a recess 13 giving access to this screw for an angular position determined by the compression key (6).
 6. Device according to one of the preceding claims, characterized by the fact that the central passage of the tube has in its external portion the shape of a cone flaring outwardly.
 7. Device according to claim 6, characterized by the fact that in the conical portion of small diameter of the internal passage of the tube (1) is disposed a split ring (14) having a triangular cross-section giving passage to the shaft (16) of the crown (17) as well as the compression joint (15).
 8. Device according to one of the preceding claims, characterized by the fact that the shaft (16) is secured to and made of one piece with the crown (17).
 9. Device according to one of claims 1 to 7, characterized by the fact that the crown (17) is mounted axially movably against the action of a spring (20) on the shaft (16) with which it is secured in rotation.
 10. Device according to claims 3 and 4, characterized by the fact that the means for driving in rotation the compression key comprise a coupling between the compression key (6) and the crown (17) that can be engaged when the crown (17) is moved against the action of the spring (20).
 11. Device according to one of the preceding claims, characterized by the fact that the screw pitch of the compression key and of the tube is of a direction opposite the direction of rotation of the crown (17) corresponding to setting a watch movement disposed in the casing (4). 